A preprocessor is provided which can insert calls
to "Control.Monad.Loc.withLoc" before every monadic statement in a module.
To invoke the preprocessor, add the pragma OPTIONS_GHC -F -pgmF MonadLoc at the top of your Haskell files together with an import for the Control.Monad.Loc module

This package provides no implementation of the Control.Monad.Loc.MonadLoc interface.
Currently the only package that does so is control-monad-exception,
but any other package can implement it and provide monadic call traces.